[Chap. XLVI UNDER-WATER ENVIRONMENTS 605 



sumer" because of the necessary respiratory and assimilatory processes 

 of the often numerous "middlemen." Each "middleman" may use up 

 in these processes as much as 90 per cent of the initial energy value of 

 the food. 



In spite of the small size of most marine plants and animals, a rapidly 

 moving feeder can secure large amounts of food in the ocean. This is 

 illustrated by the growth of the calf of the blue whale. At birth it is 

 7 meters long and weighs 2 tons, but may grow to be 23 meters long 

 and weigh as much as 60 tons at the end of two years. The food of the 

 blue whale consists entirely of plankton which includes small Crustacea. 

 The plankton passes into the mammal through the so-called "whale- 

 bone sieve." As much as two tons of plankton have been found in the 

 stomach of a mature blue whale at one time. If there are only three 

 links in the food chain of this animal, the gain in weight would implv 

 the consumption of food equivalent to 58,000 tons of algae in a period 

 of two years. It is interesting to note that whalers often locate the 

 places where whales may be found bv the presence of large quantities 

 of plankton at the surface of the water. Biologically algae and bacteria 

 are the most important of aquatic plants. The algae are described in 

 more detail in the following chapter. 



REFERENCES 



Beebe, William. The depth of the sea. Nat. Geog. Mag. 51:65-88. 1932. 

 Beebe, William. Half Mile Down. Harcoiirt, Brace & Company, Inc. 1934. 

 Birge, E. A., and C. Juday. The inland lakes of Wisconsin. Wise. Geol. and 



Nat. Hist. Survey. Bull. 64. 1922. 

 Coker, R. E. Life in the Sea. Sci. Monthly for April and May. 1938. 

 Hesse, R., W. C. Allee, and K. P. Schmidt. Eeological Animal Geographi/. 



John Wiley & Sons. 1937. Chaps. X and XI. 

 Krogh, A. Conditions of life in the ocean. Ecological Monographs. 4:421-429. 



1934. 

 Symposium: Problems of Lake Biology. A. A. A. S. Pub. No. 10. The Science 



Press. 1939. 

 Tiffany, L. H. Algae, the Grass of Many Waters. C. C. Thomas, Publisher. 



1938. 

 Welch, P. S. Limnology. McGraw-Hill Book Company, Inc. 1935. 



